era100 rear speakers fail to update when paired with Arc

The Sub and surrounds appear to fall back to your Wi-Fi connection if the main speaker's 5 gHz link isn't available.

If you assigned DHCP reserved addresses to all Sonos that often helps. Only doing some Sonos hasn't really been tested.

Did you do a network refresh to lock in the new addresses once reserved? Power down all Sonos Reboot router and controller then power the Sonos back up. 

If after all of this you still have issues submit several diagnostics. One before the update, one after the initial update fails and a third after the update with the primary speaker powered down. Then call Sonos Support and give them the diagnostic numbers and discuss your issue.

“This seems to be a Sonos bug that they refuse to acknowledge.

The issue is that from a network perspective the Arc and its subs appear as one entity all having the same MAC address (the arc connects to the network on wifi 2.4GHz and to the subs using a local 5GHz signal that does not go through the router).”

This is not a “Sonos bug” but just the way Sonos works. If it would be a bug there would be a lot more complaints - my Arc Ultra and surrounds work the same way and my surrounds are updated with the rest of my system. So there must be something special to your network that prevents the surrounds from being updated. Can you tell us what components (router, access points etc.) drive your network?

I think that the issue is that after the SUB and surrounds switch to the private 5GHz connection, the router may assume that they are no longer on the network because they have been quiet for so long and the router may give up their default IP address assignments. Then, during an update they will try to use their WiFi connection, but there may then be a conflict. Try powering down the soundbar. The SUB and surrounds should switch to WiFi. Now you can reserve the SUB and surround IP addresses.

Thanks for your help. Maybe calling it a bug was harsh, but it is definitely an repeatable issue that many others have experienced. 

The Arc and the two rear speakers are all configured in the router with fixed DHCP leases. The fact that arc -a shows all three IP address with eth same MAC address is troubling to me, not sure if this is Sonos or my router!

The Arc Ultra added the ability to connect to 5G wifi at the same time as connecting to the sub and rears, so that may be why it does not have the problem.

I will try to gather more data and contact support.

Can I clarify that in a working system, the Era100 rear speakers should be connecting to the router on 2.4GHz wifi while connecting to the Arc on 5G using Sonos net?

Is there an ‘correct order’ in commissioning the system, e.g. should the rear speakers be connected to 2.4GHz wifi first, before being joined to the Arc?

Does the problem go away if the Arc is connected to wired Ethernet?

Do I need to get a different wifi router, if so what one is known to work with Sonos?

“Can I clarify that in a working system, the Era100 rear speakers should be connecting to the router on 2.4GHz wifi while connecting to the Arc on 5G using Sonos net?

When you set up the Era 100's they could also connect to your routers 5Ghz network -  they are both 2.4 and 5Ghz capable. Once you've added them as surrounds they use a dedicated 5Ghz link to the soundbar and connect to your router via the soundbar. There are discussions about if you should call the dedicated 5GHz link between soundbar and surrounds Sonosnet, but Sonos themselves seems to regard the 5Ghz link as a kind of Sonosnet.

“Is there an ‘correct order’ in commissioning the system, e.g. should the rear speakers be connected to 2.4GHz wifi first, before being joined to the Arc?”

You'll need to set up the Era's as separate "rooms” in the app before you can bond them to the soundbar I think. When setting up they can either connect to the 2.4 or 5Ghz network of your router.

“Does the problem go away if the Arc is connected to wired Ethernet?”

Since this look like a problem specific to your router, it might. Could you try and let us know? What router are you using?

“Do I need to get a different wifi router, if so what one is known to work with Sonos?”

Again, you might. There's a list somewhere of routers that are incompatible to Sonos (thogh I cannot find it at the momen) and I've seen people here having trouble with recent ASUS routers.

From experience, same issue:

If you have ARP spoofing enabled on your router for the satellite speakers (100/300/sub ect.) then the updates will fail while the speakers remain bonded to the arc.

Remove the spoofing trap for arc and satellites and everything updates as it should - 1st time with no fiddling. WiFi band should not be an issue.

Worth checking...

You don't get to choose which band Sonos devices connect to,  only the SSID, and for optimum performance you should have a single SSID setup in your router for both bands.